The invention is directed to Schottky diodes as well as to other devices having a Schottky contact and, more particularly, to the Schottky contact metals used in such devices.
Two important properties of a Schottky diode are its forward voltage drop, VF, and its reverse blocking voltage VR. The metal that forms the Schottky contact in the Schottky diode greatly impacts the two parameters. For high blocking voltage applications, the Schottky diode requires a Schottky contact metal having a high work function to provide a large barrier height at the metal-to-semiconductor interface. However, the large barrier height also causes a higher voltage drop when the diode is forward biased. Another concern is that when the diode is reverse biased, the highest electric fields occur at the edge of the metal contact, whereas when the diode is forward biased, all of the contact area conducts the current uniformly.
Known solutions for improving the reverse biased characteristics of GaN Schottky devices also sacrifice the forward bias performance of the device, such as by increasing the forward voltage drop. It is therefore desirable to improve the reverse biased characteristics of such devices without degrading the forward voltage drop.